Oil Pump Shaft

Bob Bidonde

Bob Bidonde

Well-known member
The Model "A" oil pump has a 5/8" diameter shaft A-6608. In 1932 - 1934, the B-6608 Oil Pump shaft is undercut to 9/16" diameter between its bushing locations to increase oil flow for the pressurized oil system in the Model "B" engine. Except for the shafts, the Model "A" pump used from May 1928-1931 is the same as the Model "B" pump. The B-6608 Undercut Shaft can be used in the Model "A's" A-6608 Oil Pump, but the A-6608 5/8" Shaft should not be used in the Model "B's" oil pump.
The B-6608 9/16" diameter shaft is a desirable upgrade for the Model "A's" oil pump to increase oil flow. However, I cannot find the 9/16" shaft in any of the Model "A" parts catalogs. Is the B-6608 9/16" Diameter Oil Pump Shaft available from any parts dealer?
 
So at sustained speed will the increased flow begin to pump the sump dry? Has anyone ever really researched this? More is not always better. Look at that post from Terry Burtz this weekend, where he talks about making up some baffles to keep from flooding the valve chamber with oil.

I have a later Ford v-8 and it was discovered that those engines once over about 4,000 RPM will slowly begin to starve for oil. If you put one on a dyno without adding an extra quart the thing will lock up.

I'm always concerned about oil changes without thinking them through. The center main feed seems reasonable, but even then I like the smaller tube to feed it.
 
Bob Bidonde said:
The Model "A" oil pump has a 5/8" diameter shaft A-6608. In 1932 - 1934, the B-6608 Oil Pump shaft is undercut to 9/16" diameter between its bushing locations to increase oil flow for the pressurized oil system in the Model "B" engine. Except for the shafts, the Model "A" pump used from May 1928-1931 is the same as the Model "B" pump. The B-6608 Undercut Shaft can be used in the Model "A's" A-6608 Oil Pump, but the A-6608 5/8" Shaft should not be used in the Model "B's" oil pump.
The B-6608 9/16" diameter shaft is a desirable upgrade for the Model "A's" oil pump to increase oil flow. However, I cannot find the 9/16" shaft in any of the Model "A" parts catalogs. Is the B-6608 9/16" Diameter Oil Pump Shaft available from any parts dealer?
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More isn't always better. The stock A pump is more than adequate at doing the job it's intended to do. You do realize the B shaft you site at 9/16" is only a 1/16" different than the A shaft at 5/8? 5/8 = 10/16. Not enough of a difference to give this any thought.

April Fool's?
 
I had the A shaft turned down, and opened up the oil intake port on my speedster engine. Works fine. Increased the running oil pressure to around 5 lbs warm. Honestly, I dont know if it does any better for the engine. Flow to the mains is limited by the tubes to the journals and increased oil circulation is not going to change that. May help in some way in cooling the engine and getting more splash on the valve stems and camshaft front bearing
 
Bill Kenz told me in the 1960s that the increased oil flow was needed to keep the Model B dipper tray full at higher RPM.

It is not about the main bearings.
It is more about keeping Model B rods from starving for oil.

The larger big ends of the B rods and higher RPM splashed more oil out of the dipper tray so more oil volume was needed.

Model A gets peak HP at 2200 PRM.

Model B gets peak HP at 2600 RPM
 
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See the Ford Service Bulletin of November 1932, Page 67. The Company indicates that the B-6608 Pump Shaft can be used in the Model A for improved oil flow. The B-6608 Shaft was the service replacement for the A-6608-B Shaft.
All I want to know, is the B-6608 Undercut Shaft reproduced so it is not necessary to have the added expense of having an A-6608 Shaft machined.
 
I think the answer is no. Have never seen a n.o.s. or new production shaft, B6608. Have turned turned a few As for various project's though.
 
Berts has the A-6600 oil pump rebuild kit.

Bushings, gasket, gear and shaft with gear.

This shaft is turned down to 0.410 from .498 and has been manufactured this way for years that I know of.

Oil pump shafts have always been .498 ... not 9/16ths or 5/8th.

9/16ths is the diameter of the BORE inside the Model A oil pump HOUSING which in April 1928 was increased to 5/8ths BORE size.

So Model A pump housings came in two different versions with respect to the shaft housing BORE. Which means the correct shaft has to be used with each housing.

The 6608 part number appears in the Green Bible.
 
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My car is March 1928. I wonder if I have the old pump stored away in my garage... Interesting.
 
Modified V8 pump shaft for Model AB

John
 

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I solved the problem by installing a belt driven Aviaid dry sump pump.
Been using them for years. No shafts to worry about.
 
Pete said:
I solved the problem by installing a belt driven Aviaid dry sump pump.
Been using them for years. No shafts to worry about.
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Pete,

I have been using Dailey, Barnes and Aviaid wouldn't have it any other way on an expensive motor....

J
 
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